Telephone signaling system



K. M. LORD TELEPHONE SIGNALING SYS TEM ET AL April 29, 1941.

Filed June 8 1939 & INVENTORS Iekm 2101120? .ZTVl/rreru weir ATTORNEY.

Patented Apr. 29, 1941 warren TELEPHONE SIGNALING SYSTEM Kenneth M.Lord, Canandaigua, and Glenn E. Warren, Honcoye Falls, N. Y., assignorsto The A. E. Rittenhouse 00., Inc., Honeoye Falls, N. Y., a corporationof New York Application June 8, 1939, Serial N0. 278,122

g 2 Claims. (c1. 179-86) This invention relates to a telephone signalingsystem, with more particular reference to the type of telephone circuitemployed in what is known .as the superimposed system of ringing where abattery or direct current is superimposed on an alternating generatorcurrent, and it has for its object to afford a practical and efficientconstruction that will enable using a chime bar or chime element andsuitable striker operating means therefor such as a solenoid, in placeof the conventional vibrating ringing bell.

A further object of the invention is to afford a construction applicableto a four-party signaling circuit in which any one of the four stationsis selectible from a central office, such that the solenoid or otheractuating means for the chime element or signal is operated only at theone selected station while the other three signal operating means remainidle.

A more particular purpose of the invention is to provide at each stationof a four-party system, where a direct current can be superimposed on analternating current, a flow-controlling device such for instance as acopper oxide rectifier in series with the solenoid or othersignal-actuating means so that when one ringing key is operated toselect. and signal a particular station, the current, which travels fromone side of the line to ground through two of the stations will bepermitted to pass freely through the solenoid at only the one selectedstation, the direct current through the other station on the same sideof the line being retarded by the copper oxide rectifier to such anextent as to render the solenoid at that station idle.

To these and other ends, the invention consists in the construction andarrangement of parts that will appear clearly from the followingdescription when read in conjunction with the accompanying drawing, thenovel features being pointed out in the claims following thespecification.

In the drawing:

Fig. 1 is a diagrammatic view of a conventional four-party superimposedsystem of signaling, showing the circuit arrangement at each of the fourstations and the general plan of ringing keys at the central station;

Fig. 2 is an enlarged sectional View on the line 22 of Fig. 1 showingthe construction and arrangement of the solenoid striker mechanism andchime bars;

Fig. 3 is a detail sectional view of one of the copper oxide rectifiers;

Fig. 4 is a diagrammatic view showing the above the zero axis.

symmetrical form of current wave the alternating generator, and

Fig. 5 is a similar view showing the form of the alternating wave asmodified by the superimposed produced by 1 direct battery current.

Referring more particularly to the drawing inwhich like referencenumerals'refer to the same parts throughout the several views, thecircuit shown includes four stations, stations Nos. 1 and 2 beingconnected between one side of the line H, known as the tip, and ground,and stations Nos.- 3 and 4 being connected'between the other'sid'e ofthe line l2, known as the ring, and ground. The line is adapted to beconnected withthe central oflice through the conventional plug and jackl3 and I4 respectively, while I, 2, 3 and 4 desighate the respectiveringing keys at centralfor signaling the corresponding stations.

The alternating generator is indicated at G,

and it is connected through battery A to the ringing keys I and 3 tocarry the positively biased current to opposite sides of the line, andgenerator G is also connected through battery B to ringing keys 2 and 4to carry the negatively" biased current to opposite sides of the linerespectively. The batteries A and B act to superimpose their current onthe alternating current" and to shift the wave of the latter in apositive or negative direction, depending upon which ringing key isoperated and the battery connected thereto. The alternating generator isalso connected to ground and to the opposite sides of the line throughthe ringing keys as shown. Fig. I shows the sine-wave form of theaIternating current produced by the generator before passing through oneof the batteries, the potential wave being symmetrical above and belowthe zero axis, while in Fig. 2 is illustrated the form of Wave after thedirect battery current is superimposed on the alternating current bypassing the latter through a battery, resulting in pulsa tions thatextend to a greater extent above the zero axis and to a lesser extentbelow the zero axis than the alternating current alone. Fig; 2 shows theeifect where the alternating wave has been shifted in a positivedirection by the battery current, and when shifted in a negativefdi-frection, the corresponding increased wave would be below the zero axisand the decreased wave At each station there is provided a rela y l5,induction coil l6, condenser l1, telephone handset 18, and the terminalplate IS, in accordance with known practice in the art. Each relay isconnected in series with its condenser across the two sides of the line,so that the alternating potential between the two sides of the line willcause the condenser to pass alternating current to its relay, so thatthe relay contacts are closed at all stations when any ringing key isoperated.

The present invention has to do with the ar- 'rangement at each stationof a signal such as a chime bar and means for operating the signal orstriking the chime bar such as a solenoid, together with a current flowcontrrolling device which acts to render the current inefieotive whentraveling in one direction on a given side of the line, and thus permitsthe current to operate only one solenoid and signal on one side of theline for each ringing key.

This is accomplished in the arrangement shown by providing in theconductor 20, which leads from the tip side of the line H to groundthrough the relay IS, a solenoid 2| and in series therewith a currentflow-controlling device preferably in the form of a copper oxiderectifier 22. The parts just referred to are duplicated at each stationso that it is unnecessary to describe more than one, and as appears fromthe drawing, the solenoid and rectifier at'stations Nos. 1 and 2 arebetween the tip. side of the line and ground, the rectifiers beingarranged oppositely so that each one permits free passage of directcurrent in one direction only, and retards the passage of direct currentin the opposite direction, while the solenoid and rectifier at stationsNos. 3 and 4 are between the ring side of the line and ground, and therectifiers also oppositely arranged so as to permit free passage ofcurrent and operation of the solenoid when direct current is travelingin one direction only.

The rectifier shown, which is illustrated in detail in Fig. 3, is of thetype consisting of a series of copper washers 23, each having a copperoxide coating 24 on one side thereof, the disks being separated by leadwashers 25 and all assembled and held on a suitable sleeve 26. It willbe understood that the copper oxide coating appears on one side only ofthe copper washers, and current passes freely through such a unit onlyin the direction from the oxidev coating to the copper base or washer,Whereas when current is traveling in the opposite direction, substantialresistance is ofl'ered which, in the present installation, is sufficientto retard the direct current to a point where it will not. operate thesolenoid 2|.

With this explanation, it will be understood that by arranging therectifiers at stations Nos. 1 and 2 oppositely, the direct current fromringing key I orringing key 2 will operate only one of the solenoidsbecause the rectifier at the other station will offer sufiicientresistance to the direct cur-rent to prevent the solenoid being operatedat that station. While there is a slight amount of current in theopposite direction for a portion of the cycle, as indicated by theshaded portion of the curve below the line in Fig. 5, this is for lessthan half the cycle and the current is of insufficient value to operatethe solenoid at the other of the two stations.

In, thestructure shown, the solenoid 2 I see Fig. 2, controls theplunger 21 carrying strikers 218' at its opposite ends which travelthrough openings ,29 in the resonance chambers 38 and engage chime barsor chime elements 3| mounted in said resonance chambers.

In operation, when the current is in the proper direction to operate thesolenoid 2|, its plunger is. moved upwardly to strike the top chime bar3 i, and upon, opening the signaling circuit at central, the solenoid isdeenergized and plunger 2'! drops by gravity so that its lower strikerengages the lower chime bar 3! afterwhich the spring 32 returns theplunger to normal position, removing the striker from engagement with.the lower chime bar. Thus a double note or chime signal is givenwhenever it is desired to select a signal and particular station. 7

In the operation of the circuit as shown, assuming that it is desired tosignal station No. 1, ringing key I is actuated, permitting thealternating current with the positive battery current superimposedthereon to pass to the tip side ll of the line and thence through thesolenoid, rectifier and relay at station No. 1 to ground, thearrangement of the rectifier at station No. 1 being such as to permitfree passage of the'alternating current with superimposed positivebattery current, and thereby operate the solenoid and chime bars.

At the same time, the current attempts to travel similarly at stationNo. 2 but the rectifier at that station is oppositely arranged, andprevents passage of the positively biased current, while such current asmay pass through the rectifier at station No. 2 has insufficient valueto operate the solenoid, and it remains idle.

To signal station No. 2, ringing key 2 is operated, causing analternating current with a negatively superimposed battery current topass through the circuits at stations Nos. 1 and 2, and by reason of therelation of the rectifiers, such current passes freely only at stationNo. 2, actuating its solenoid and chime signal While the one at stationNo. 1 remains idle.

It will be understood that when ringing keys l or 2 are operated, thecurrent travels from the tip side of the line through the respectivestation circuits to ground, and there is not suficient potential on thering side of the line to operate stations Nos. 3 and 4. These areconnected hetween the ring side of the line and ground and are subjectto operation when ringing key3 or r 4 is operated, similarly as alreadydescribed with respect to stations Nos. 1 and 2.

While the invention has been described with reference to a particularembodiment, it is not limited to the details and arrangement shown, andthis application is intended to cover such modifications or adaptationsas may come within the purposes of the invention or the scope of thefollowing claims.

We claim:

1. In a superimposed signaling system for a telephone circuit includinga plurality of subscribers stations, a central station, signalingcircuits connecting the central station with the subscribers stations,and means at the central station for feeding a direct currentsuperimposed on an alternatingv current over said signaling circuitsfrom the central station to the subscribers stations, the combinationwith a chime signal -including chime element and resonance chamber ateach subscribers station, of a solenoid at each subscribers stationhaving a plunger carrying a striker engageable with said chime element,said solenoid beingin the said subscribers circuit and operated by saidsignaling current from the central station, a rectifier interposed inthe circuit at each subscribers station in serieswith said solenoid andacting to permit free passage of direct current and consequent operationofthe solenoid when the direct current is traveling in one direction andto prevent passage of an effec? tive amount of current and consequentlyrender said solenoid idle when the direct current is traveling in theopposite direction, said rectifiers being oppositely arranged at the twostations whereby the solenoid and chime signal may be selectivelyoperated at any subscribers station by means of current from the centralstation.

2. In a superimposed signaling system for a telephone circuit includingfour subscribers stations, a central station, signaling circuitsconnecting the central station with the subscribers stations, and meansat the central station for feeding a direct current superimposed on analternating current over said signaling circuits from the centralstation to the subscribers stations, the combination with a chime signalincluding a chime element and resonance chamber at each subscribersstation, of a solenoid at each subscribers station having a plungercarrying a striker engageable with said chime element, said solenoidbeing in the said subscribers circuit and operated by said signalingcurrent from the central station, a rectifier interposed in the circuitat each subscribers station in series with said solenoid and acting topermit free passage of direct current and consequent operation of thesolenoid when the direct current is traveling in one direction and toprevent passage of an effective amount of current and consequentlyrender said solenoid idle when the direct current is traveling in theopposite direction, the solenoid and rectifier at two of the stationsbeing connected between one side of the line and the ground and thesolenoid and rectifier at the remaining two stations being connectedbetween the other side of the line and the ground, and the rectifiersbeing oppositely arranged at each of the two stations on one side of theline whereby a solenoid and chime signal may be selectively operated atany subscribers station by means of current from the central station.

KENNETH M. LORD. GLENN E. WARREN.

